This invention relates to the real-time monitoring and control of air quality in a work or living space, and is more particularly concerned with devices that provide a measurement of health quality and contaminant concentration levels of ambient air. The invention is also concerned with control devices for controlling operation of air treatment and removal of particulates in connection with a room air health and comfort unit.
In order to provide satisfactory air quality in an environmental work space or living space, it is desirable to obtain an indication of the contaminant concentrations in the space, both in terms of gas or vapor concentrations (i.e., CO, SO.sub.2 or other noxious gases), or airborne particulate concentrations, (i.e., dust, aerosol droplets, bacteria, spores, pollen, and viruses). Then it is necessary to compare the measured values with threshold limit values (TLVs) which correspond to the levels of contaminant concentration to which humans can be continuously exposed without significant adverse health risk. Levels higher than TLVs represent air quality that is marginal to unacceptable.
In the United States, threshold limit values are established by government agencies such as the National Institute of Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Agency (OSHA) based on information compiled by the American Conference of Governmental and Industrial Hygienists (ACGIH) with additional published data from the Environmental Protection Agency (EPA), and standards from the American Society of Heating, Refrigeration and Air Conditioning Engineers.(ASHRAE)
However, measurement of air quality has required special, complex equipment to be used by specially trained personnel. It was not possible for a lay person to obtain a real-time reading of air quality in an environmental work or living space. In addition, there has not been any suitable combined control circuitry available for controlling room air quality equipment, for controlling comfort factors, such as heat and relative humidity, as well as health factors such as particulate and gas concentrations to remain below their respective TLVs. There has been no control circuit provided for environment control equipment to monitor and control air quality based on temperature, relative humidity, particulates and aerosols concentration or gas concentration levels.